Just in time for Halloween creepiness: some scientists now suspect that a leading cause of death for North American moose is the famously bloodthirsty winter tick. Apparently, these ticks are extra numerous thanks to the effects of climate change, and are literally sucking the poor animal dry. Yuck.

At least, that’s a leading theory. There’s no clear consensus on exactly what’s killing them. But according to the New York Times, of Minnesota’s two separate moose populations, one has dropped 25 percent a year over recent years, from 8,000 to 3,000, and the other has fallen from 4,000 to under 100. It’s gotten so bad that local officials have put an end to all moose hunting — a serious consequence in many northern communities.

The dominant theory as to why the moose are dying off in North America is that climate change is causing shorter winters, meaning fewer of the parasitic ticks are dying. More ticks equal more tick infestations for the moose which, unlike deer, don’t groom themselves.

This leads moose to rub and tug on areas of their bodies where ticks are feeding. Eventually, the moose have large patches of missing or broken hair, called “ghost” moose, because the white base of the hair shaft is all that’s left.

These phantom moose, without their full coats, are then susceptible to hypothermia in the cooler weather. And in some places, the ticks drink so much blood that the moose becomes anemic, and eventually dies.

Ticked Off

Unfortunately, the worst may be yet to come this year, as most moose deaths happen in the fall. And getting to the bottom of the mystery may prove tricky because moose are hard to study, thanks to their solitary nature and quickly decomposing fat stores that make field autopsies nearly useless. Minnesota scientists hope a program of tagging and monitoring wild moose will help. For the sake of these elusive and elegant brutes, let’s hope it does.